Gale crater is also thought to harbor clues
of ancient
water activity on the Martian surface, and one
of Curiosity's primary tasks will be to root around for
evidence that Mars is, or was, capable
of supporting microbial life.
Indeed, strong observational
evidence and results from modeling studies indicate that, at least over the last 50 years, human
activities are a major contributor to climate change.Direct human impact is through changes in the concentration
of certain trace gases such as carbon dioxide, chlorofluorocarbons, methane, nitrous oxide, ozone, and
water vapor, known collectively as greenhouse gases.